如何使用 Java 从系统相机拍摄快照

问题描述

如何使用 Java 从系统相机拍摄快照。

解决方案

以下是使用 Java 从系统相机拍摄快照的程序。

import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.awt.image.WritableRaster;

import java.io.FileNotFoundException;
import java.io.IOException;

import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.image.ImageView;
import javafx.scene.image.WritableImage;
import javafx.stage.Stage;

import org.opencv.core.Core; 
import org.opencv.core.Mat; 
import org.opencv.videoio.VideoCapture;  

public class TakingSnapshotUsingCamera extends Application { 
   Mat matrix = null; 

   @Override 
   public void start(Stage stage) throws FileNotFoundException, IOException {        
      
    //从相机捕获快照
    TakingSnapshotUsingCamera obj = new TakingSnapshotUsingCamera();
    WritableImage writableImage = obj.capureSnapShot();
    
    //设置图像视图
    ImageView imageView = new ImageView(writableImage);
    
    //设置图像视图的适合高度和宽度
    imageView.setFitHeight(400);
    imageView.setFitWidth(600);
    
    //设置图像视图的保留比例
    imageView.setPreserveRatio(true);
    
    //创建 Group 对象
    Group root = new Group(imageView);
    
    //创建场景对象
    Scene scene = new Scene(root, 600, 400);
    
    //设置stage(舞台)标题
    stage.setTitle("Capturing an image");
    
    //将场景添加到stage(舞台)
    stage.setScene(scene);
    
    //显示stage(舞台)内容
    stage.show();
   }
   
   public WritableImage capureSnapShot() { 
      WritableImage WritableImage = null; 

        //加载 OpenCV 核心库
        System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
        
        //实例化 VideoCapture 类 (camera:: 0)
        VideoCapture capture = new VideoCapture(0);
        
        //从摄像头读取下一个视频帧
        Mat matrix = new Mat();
        capture.read(matrix);
        
        //如果摄像头已打开
        if(capture.isOpened()) { 
         
         //如果有下一个视频帧
         if (capture.read(matrix)) {      
            
            //从矩阵创建 BuffredImage
            BufferedImage image = new BufferedImage(matrix.width(), matrix.height(), 
               BufferedImage.TYPE_3BYTE_BGR); 
            
            WritableRaster raster = image.getRaster(); 
            DataBufferByte dataBuffer = (DataBufferByte) raster.getDataBuffer(); 
            byte[] data = dataBuffer.getData(); 
            matrix.get(0, 0, data); 
            this.matrix = matrix; 

            //创建可写映像
            WritableImage = SwingFXUtils.toFXImage(image, null); 
         } 
      }
      return WritableImage; 
   }  
   public static void main(String args[]) {  
      launch(args);  
   }  
}

输出